1. Field of the Invention
The present invention relates to a multicylinder internal combustion engine, especially to a cylinder-deactivatable, multicylinder internal combustion engine.
2. Background of the Invention
For example, inline 4-cylinder engines include those capable of deactivating four engine valves, which each cylinder is provided with, selectively in combinations of one intake and exhaust valves and the other intake and exhaust valves. By providing an engine with a function that can selectively deactivate engine valves as mentioned above, the operation of the engine can be controlled in four patterns consisting in combination of a case that the intake and exhaust valve combinations are both closed, cases that the one intake and exhaust valve combination is closed and the other intake and exhaust valve combination is closed, respectively, and a case that the intake and exhaust valve combinations are both operated, all for each cylinder (See Japanese Patent Laid-open No. 2004-293379, for example).
The above-described conventional 4-cylinder engine is, however, accompanied by a problem in that its control becomes complex, because the four patterns of cylinder operation state exist and the deactivation state of the intake and exhaust valves in each cylinder exists in two patterns, one being the case that all of the intake and exhaust valves are disabled, and the other the case that some of the intake and exhaust valves are disabled.